American troops also killed the man's wife after a firefight as they tried to capture him Friday in the northern neighborhood of Azamiyah in Baghdad, the military said.
Mahir Ahmad Mahmud al-Zubaydi, also known as Abu Assad or Abu Rami, allegedly directed the insurgent cell believed to be responsible for nearly simultaneous car bomb and suicide attacks Thursday, according to the statement.
Iraqi police and hospital officials have said some two dozen people were killed in Thursday's attacks targeting two Shiite mosques in Baghdad.
The victims were attending prayers marking Eid al-Fitr, the religious holiday that comes at the end of the Islamic fasting month of Ramadan.
Those attacks and others during the Islamic holy month have raised fears that al Qaeda in Iraq is trying to provoke Sunni-Shiite reprisal killings as U.S.-led forces begin to draw down.
Gen. Ray Odierno, the top U.S. commander in Iraq, said Shiites were "showing very much restraint" and promised to continue targeting the insurgent network.
"I think we've made some good inroads inside of the network that was doing this," he told reporters today.
Al-Zubaydi was one of the most senior insurgents to be killed by U.S. forces as they seek to shore up recent security gains that have driven the level of violence to its lowest point in more than four years.
His death will be a major blow to al Qaeda in Iraq even as the group's recruiting efforts have been "severely curbed" by a decision by many Sunnis to join forces with the Americans in the fight against it, military spokesman Rear Adm. Patrick Driscoll said.
"His removal from the AQI network will send shockwaves through Baghdad's terrorist bombing networks," Driscoll said in the statement.
The military also blamed al-Zubaydi for several car bombings and mortar attacks in Baghdad's main Shiite district of Sadr City in 2006 and 2007, including a series of blasts that killed more than 200 people on Nov. 23, 2006.
That was one of the deadliest attacks to strike the Iraqi capital amid rampant sectarian violence and attacks against U.S. forces.
Al-Zubaydi also was believed to have planned and participated in abductions and videotaped executions, including one in which he was seen shooting one of four kidnapped Russians, according to the statement.
The Russian embassy workers were abducted in June 2006 after an attack on their car in Baghdad's Mansour neighborhood. They were later killed, along with a fifth Russian.
The military also said al-Zubaydi was reportedly responsible for a May 1 car bombing that killed a U.S. soldier in Baghdad, as well as attacks in Salahuddin and Diyala provinces to the north of the capital.
The military said al-Zubaydi was originally a member of the Sunni insurgent group Ansar al-Islam and joined al Qaeda in Iraq in 2004.
He was the terror network's military "emir" in eastern Baghdad "before taking over responsibility for all terrorist operations there this year," the military said.
The statement said the information about al-Zubaydi came from detained insurgents.
On Friday, U.S. troops came under fire after surrounded a building that was said to be housing al-Zubaydi in Azamiyah, a mainly Sunni neighborhood in northern Baghdad.
"Acting in self-defense, coalition forces returned fire, killing Abu Rami and a female," the statement said. Tech. Sgt. Chris Stagner, another U.S. military spokesman, said the woman was al-Zubaydi's wife and was not a suspect.
The American troops then evacuated several children from the house before destroying ordnance inside in a controlled detonation that set fire to the building, the military said, adding it evacuated surrounding buildings as a precaution while the blaze was extinguished.
Kurds' Cross-Border Attack Kills 15 Turks
The military says the overnight battle in southern Turkey involved heavy weapons fired by the rebels at a Turkish military outpost in Aktutun.
The private TV station CNN-Turk says the Turkish military fought back, killing 23 Kurdish rebels.
Turkey's military confirmed in a statement that its soldiers returned fire, killing some rebels, but said it could not immediately say how many.
It appeared to be the deadliest attack by Kurdish rebels against Turkey's military in several months. The rebels, based in south Turkey and north Iraq, have been fighting for autonomy since 1984.
Poland Ends Military Role In Iraq
Poland has marked the end of its military mission to Iraq with a ceremony at its main base south of Baghdad.
Poland is one of several countries in the U.S.-led coalition to withdraw from Iraq.
The White House has said the withdrawals don't mean international support is dwindling but that security gains and increasingly capable Iraqi forces are letting outside forces do more with less.
The top U.S. commander in Iraq Gen. Ray Odierno says there's still work to be done.
He told reporters after Saturday's ceremony in Diwaniyah that "to go back to complete normalcy it's gonna take awhile."
Poland sent combat troops into Iraq as part of the U.S.-led coalition and had 2,300 troops deployed there at its peak. That has been reduced to about 900, who are being pulled out this month.